As already known, the use of a two-stroke engine was mainly limited to motorcycle use, this was above all due to the reduced number of components and consequent simple structure.
Other positive aspects of a two-stroke engine, compared to a four-stroke, are the elevated power produced with the same displacement and a more regular torque thanks to the availability of a power stroke for each revolution of the drive shaft.
In the automotive field, negative aspects have however prevailed over these advantages: greater consumption compared to the four-stroke, emission of pollutants, the need for more frequent maintenance.
Consumption and emissions, in particular, are subject to increasingly stringent regulations and greater attention from the public.
All manufacturers are committed to improving the performance of four-stroke engines essentially on two fronts: on the one hand by trying to make the best use of fuel in the combustion chamber (hence small engines with small combustion chambers for maximum efficiency, direct injection and supercharging), and on the other improving mechanical efficiency by reducing friction and reducing surge losses, by using effective but costly devices that change the phase and the valve lift; it is worth remembering that in a normal four-stroke engine the mechanical losses under maximum power reach approximately 20% of the engine's maximum power.
In an engine designed for city traffic, and therefore mainly used at medium-low speed, and with MEP values around 20-30% of the maximum MEP, friction and surge losses seriously affect consumption.
A two-stroke engine at 30% of the MEP has half of the friction and one third of the surge losses of a four-stroke engine; at 100% of the MEP the friction losses for the two-stroke will remain under approximately 20%.
When analyzing the typical operating range of cars with small engines in city traffic, the specific consumption indicated for a two-stroke engine fueled by direct gasoline injection is about 30% lower than a four-stroke with the same performance.
At this point it appears logical to pose the problem of whether a new concept two-stroke engine is a valid alternative to a four-stroke in the field of light transportation, and particularly within a predominantly urban environment.